Nitriding has been a conventional way of improving the wear resistance and seize resistance of jigs and tools (such as dies) for metal working. Recently, attempts are being made to replace it with vapor phase coating such as PVD as a measure of improving wear resistance and seize resistance. For example, Japanese Patent Laid-open No. 2000-144376 discloses the improvement of slidability by formation of a complex nitride containing at least two species of Cr, Al, Ti, and V. Japanese Patent Laid-open Nos. 2002-307128 and 2002-307129 disclose a surface-coated die excelling in wear resistance and seize resistance which has a coating film of nitride, carbide, or carbonitride of at least one species of Ti, V, Al, Cr, and Si and an optional second coating film of sulfide of Ti, Cr, and Mo (as remainder). Japanese Patent Laid-open No. 2000-1768 discloses a surface-treated material excelling in wear resistance and seize resistance which is composed of hard nitride and MoS2 formed thereon.